Interaction-driven spin precession in quantum-dot spin valves

Abstract

We analyze spin-dependent transport through spin valves composed of an interacting quantum dot coupled to two ferromagnetic leads. The spin on the quantum dot and the linear conductance as a function of the relative angle $θ$ of the leads' magnetization directions is derived to lowest order in the dot-lead coupling strength. Due to the applied bias voltage spin accumulates on the quantum dot, which for finite charging energy experiences a torque, resulting in spin precession. The latter leads to a non-trivial, interaction-dependent, $θ$-dependence of the conductance. In particular, we find that the spin-valve effect is reduced for all $θ\neq π$.

5 pages, 3 figures, version to be published in Phys. Rev. Lett